"without any external power source. Capacity is substantially larger than that of an EEPROM, making these chips a popular choice for digital cameras and desktop PC BIOS chips. Flash memory devices use two different logical technologies—NOR and NAND—to map data. NOR flash provides high-speed random access, reading and writing data in specific memory locations; it can retrieve as little as a single byte. NAND flash reads and writes sequentially at high speed, handling data in small blocks called pages, however it is slower on read when compared to NOR. NAND flash reads faster than it writes, quickly transferring whole pages"
"ensure proper programming. EPROM An EPROM (rarely EROM), or erasable programmable read-only memory, is a type of memory chip that retains its data when its power supply is switched off. Computer memory that can retrieve stored data after a power supply has been turned off and back on is called non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages than those normally used in digital circuits. Once programmed, an EPROM can be erased by exposing it to strong ultraviolet light source (such as from a mercury-vapor light). EPROMs are easily recognizable"
"– EEPROM, SSD, NAND, etc. Non-volatile memory is typically used for the task of secondary storage, or long-term persistent storage. The most widely used form of primary storage today is a volatile form of random access memory (RAM), meaning that when the computer is shut down, anything contained in RAM is lost. However, most forms of non-volatile memory have limitations that make them unsuitable for use as primary storage. Typically, non-volatile memory costs more, provides lower performance, or have limited lifetime compared to volatile random access memory. Non-volatile data storage can be categorized into electrically addressed systems (read-only memory) and"
"EEPROM EEPROM (also EPROM) stands for Electrically Erasable Programmable Read-Only Memory and is a type of non-volatile memory used in computers, integrated in microcontrollers for smart cards and remote keyless system, and other electronic devices to store relatively small amounts of data but allowing individual bytes to be erased and reprogrammed. EEPROMs are organized as arrays of floating-gate transistors. EEPROMs can be programmed and erased in-circuit, by applying special programming signals. Originally, EEPROMs were limited to single byte operations which made them slower, but modern EEPROMs allow multi-byte page operations. It also has a limited life for erasing and reprogramming,"
"EPROM An EPROM (rarely EROM), or erasable programmable read-only memory, is a type of memory chip that retains its data when its power supply is switched off. Computer memory that can retrieve stored data after a power supply has been turned off and back on is called non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages than those normally used in digital circuits. Once programmed, an EPROM can be erased by exposing it to strong ultraviolet light source (such as from a mercury-vapor light). EPROMs are easily recognizable by the transparent"
"computer storage devices (e.g. hard disk drives, floppy disks and magnetic tape), optical discs, and early computer storage methods such as paper tape and punched cards. Forthcoming non-volatile memory technologies include FeRAM, CBRAM, PRAM, STT-RAM, SONOS, RRAM, racetrack memory, NRAM, 3D XPoint, and millipede memory. A third category of memory is ""semi-volatile"". The term is used to describe a memory which has some limited non-volatile duration after power is removed, but then data is ultimately lost. A typical goal when using a semi-volatile memory is to provide high performance/durability/etc. associated with volatile memories, while providing some benefits of a true"
"dance (i.e. prom) called EEPROM since 2012. EEPROM EEPROM (also EPROM) stands for Electrically Erasable Programmable Read-Only Memory and is a type of non-volatile memory used in computers, integrated in microcontrollers for smart cards and remote keyless system, and other electronic devices to store relatively small amounts of data but allowing individual bytes to be erased and reprogrammed. EEPROMs are organized as arrays of floating-gate transistors. EEPROMs can be programmed and erased in-circuit, by applying special programming signals. Originally, EEPROMs were limited to single byte operations which made them slower, but modern EEPROMs allow multi-byte page operations. It also has"
"Nonvolatile BIOS memory Nonvolatile BIOS memory refers to a small memory on PC motherboards that is used to store BIOS settings. It is traditionally called CMOS RAM because it uses a volatile, low-power complementary metal-oxide-semiconductor (CMOS) SRAM (such as the Motorola MC146818 or similar) powered by a small ""CMOS"" battery when system and standby power is off. The typical NVRAM capacity is 256 bytes. The CMOS RAM and the real-time clock have been integrated as a part of the southbridge chipset and it may not be a standalone chip on modern motherboards. The memory battery (aka motherboard, CMOS, real-time clock"
"""non-volatile"" forms of semiconductor memory exist. In modern computers, primary storage almost exclusively consists of dynamic volatile semiconductor memory or dynamic random-access memory. Since the turn of the century, a type of non-volatile semiconductor memory known as flash memory has steadily gained share as off-line storage for home computers. Non-volatile semiconductor memory is also used for secondary storage in various advanced electronic devices and specialized computers that are designed for them. As early as 2006, notebook and desktop computer manufacturers started using flash-based solid-state drives (SSDs) as default configuration options for the secondary storage either in addition to or instead"
"the power to the memory chip is turned off. However it can be faster and less expensive than non-volatile memory. This type is used for the main memory in most computers, since data is stored on the hard disk while the computer is off. Major types are: Nonvolatile memory preserves the data stored in it during periods when the power to the chip is turned off. Therefore, it is used for the memory in portable devices, which don't have disks, and for removable memory cards among other uses. Major types are: Semiconductor memory Semiconductor memory is a digital electronic data"
"PC XT. The use of ROM to store such small amounts of data has disappeared almost completely in modern general-purpose computers. However, Flash ROM has taken over a new role as a medium for mass storage or secondary storage of files. Classic ""mask-programmed ROM"" chips are integrated circuits that physically encode the data to be stored, and thus it is impossible to change their contents after fabrication. Other types of non-volatile solid-state memory permit some degree of modification: By applying write protection, some types of reprogrammable ROMs may temporarily become read-only memory. There are other types of non-volatile memory which"
"technology, which is used Renesas Electronics' flash memory integrated in single-chip microcontrollers until today. In 1972, one of electrically re-programmable non-volatile memory was invented by Fujio Masuoka at Toshiba, who is also known as the inventor of ""flash memory"". Most of major semiconductor manufactures, such as Toshiba, Sanyo (later, ON Semiconductor), IBM, Intel, NEC (later, Renesas Electronics), Philips (later, NXP Semiconductors), Siemens (later, Infineon Technologies), Honeywell (later, Atmel), Texas Instruments, studied, invented, and manufactured some electrically re-programmable non-volatile devices until 1977. The theoretical basis of these devices is ""Avalanche"" hot-carrier injection. But in general, programmable memories, including EPROM, of early"
"Historically, ""memory"" has been called ""core memory"", ""main memory"", ""real storage"" or ""internal memory"". Meanwhile, non-volatile storage devices have been referred to as ""secondary storage"", ""external memory"" or ""auxiliary/peripheral storage"". ""Primary storage"" (also known as ""main memory"" or ""internal memory""), often referred to simply as ""memory"", is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them as required. Any data actively operated on is also stored there in uniform manner. Historically, early computers used delay lines, Williams tubes, or rotating magnetic drums as primary storage. By 1954, those unreliable methods were"
"for a more persistent memory. Known as NVDIMM-P, it is expected to be released by 2018. Early computers used core and drum memory systems which were non-volatile as a byproduct of their construction. The most common form of memory through the 1960s was magnetic-core memory, which stored data in the polarity of small magnets. Since the magnets held their state even with the power removed, core memory was also non-volatile. Other memory types required constant power to retain data, such as vacuum tube or solid-state flip-flops, Williams tubes, and semiconductor memory (static or dynamic RAM). Advances in semiconductor fabrication in"
"non-volatile memories exist that allow random access for read operations, but either do not allow write operations or have other kinds of limitations on them. These include most types of ROM and a type of flash memory called ""NOR-Flash"". Integrated-circuit RAM chips came into the market in the early 1970s, with the first commercially available DRAM chip, the Intel 1103, introduced in October 1970. Early computers used relays, mechanical counters or delay lines for main memory functions. Ultrasonic delay lines could only reproduce data in the order it was written. Drum memory could be expanded at relatively low cost but"
"by permanently enabling or disabling selected transistors, such that the memory cannot be altered. Writeable variants of ROM (such as EEPROM and flash memory) share properties of both ROM and RAM, enabling data to persist without power and to be updated without requiring special equipment. These persistent forms of semiconductor ROM include USB flash drives, memory cards for cameras and portable devices, and solid-state drives. ECC memory (which can be either SRAM or DRAM) includes special circuitry to detect and/or correct random faults (memory errors) in the stored data, using parity bits or error correction codes. In general, the term"
"Volatile memory Volatile memory, in contrast to non-volatile memory, is computer memory that requires power to maintain the stored information; it retains its contents while powered on but when the power is interrupted, the stored data is quickly lost. Volatile memory has several uses including as primary storage. In addition to usually being faster than forms of mass storage such as a hard disk drive, volatility can protect sensitive information, as it becomes unavailable on power-down. Most of the general-purpose random-access memory (RAM) is volatile. There are two kinds of volatile RAM: dynamic and static. Even though both types need"
"Read-only memory Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM can only be modified slowly, with difficulty, or not at all, so it is mainly used to store firmware (software that is closely tied to specific hardware, and unlikely to need frequent updates) or application software in plug-in cartridges. Strictly, ""read-only memory"" refers to memory that is hard-wired, such as diode matrix and the later mask ROM (MROM), which cannot be changed after manufacture. Although discrete circuits can be altered in principle, integrated circuits (ICs) cannot, and are"
"In industry parlance, RAM chips were ""volatile"". Read-only memory (ROM) chips, by contrast, were ""nonvolatile""—that is, the information encoded in the chip was fixed and unchangeable. But the process for programming ROM memories was time-consuming and cumbersome. Typically, the data had to be “burned in” at the factory: physically embedded on the chip through a process called “masking” that generally took weeks to complete. And once programmed, the data in the ROM chip could not be altered. The EPROM was nonvolatile and reprogrammable. It was the catalyst for innovations and developments that led to flash memory technology. The EPROM was"
"some older IBM PC compatibles, or a 3-cell NiCd CMOS battery that looks like a ""barrel"" (common in Amiga and older IBM PC compatibles), which serves the same purpose. These motherboards often have a four pin straight header, with pin two missing, to connect an external 3.6v battery, such as the Tadiran TL-5242/W, when their soldered on batteries die. Nonvolatile BIOS memory Nonvolatile BIOS memory refers to a small memory on PC motherboards that is used to store BIOS settings. It is traditionally called CMOS RAM because it uses a volatile, low-power complementary metal-oxide-semiconductor (CMOS) SRAM (such as the Motorola"
"as non-volatile storage for programs in most early stored-program computers, such as ENIAC after 1948. (Until then it was not a stored-program computer as every program had to be manually wired into the machine, which could take days to weeks.) Read-only memory was simpler to implement since it needed only a mechanism to read stored values, and not to change them in-place, and thus could be implemented with very crude electromechanical devices (see historical examples below). With the advent of integrated circuits in the 1960s, both ROM and its mutable counterpart static RAM were implemented as arrays of transistors in"
"the data center and cloud computing. NVDIMM A non-volatile dual in-line memory module (NVDIMM) is a type of random-access memory for computers. Non-volatile memory is memory that retains its contents even when electrical power is removed, for example from an unexpected power loss, system crash, or normal shutdown. ""Dual in-line"" identifies the memory as using the DIMM package. NVDIMMs improve application performance, data security, and system crash recovery time. They enhance solid-state drive (SSD) endurance and reliability. ""Non-volatile"" products may use volatile memory during normal operation and dump the contents into non-volatile memory if the power fails, using an on-board"
"now reaching a million operations in modern EEPROMs. In an EEPROM that is frequently reprogrammed while the computer is in use, the life of the EEPROM is an important design consideration. Flash memory is a type of EEPROM designed for high speed and high density, at the expense of large erase blocks (typically 512 bytes or larger) and limited number of write cycles (often 10,000). There is no clear boundary dividing the two, but the term ""EEPROM"" is generally used to describe non-volatile memory with small erase blocks (as small as one byte) and a long lifetime (typically 1,000,000 cycles)."
"NVDIMM A non-volatile dual in-line memory module (NVDIMM) is a type of random-access memory for computers. Non-volatile memory is memory that retains its contents even when electrical power is removed, for example from an unexpected power loss, system crash, or normal shutdown. ""Dual in-line"" identifies the memory as using the DIMM package. NVDIMMs improve application performance, data security, and system crash recovery time. They enhance solid-state drive (SSD) endurance and reliability. ""Non-volatile"" products may use volatile memory during normal operation and dump the contents into non-volatile memory if the power fails, using an on-board backup power source. Volatile memory is"
"Regenerative capacitor memory Regenerative capacitor memory is a type of computer memory that uses the electrical property of capacitance to store the bits of data. Because the stored charge slowly leaks away, these memories must be periodically regenerated (i.e. read and rewritten, also called refreshed) to prevent data loss. Other types of computer memory exist that use the electrical property of capacitance to store the data, but do not require regeneration. However these have either been somewhat impractical (e.g., the Selectron tube) or are usually considered to be read-only memory (e.g., EPROM, Flash memory) because writing takes significantly longer than"
"and abandonware for preservation/sharing purposes. Read-only memory Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM can only be modified slowly, with difficulty, or not at all, so it is mainly used to store firmware (software that is closely tied to specific hardware, and unlikely to need frequent updates) or application software in plug-in cartridges. Strictly, ""read-only memory"" refers to memory that is hard-wired, such as diode matrix and the later mask ROM (MROM), which cannot be changed after manufacture. Although discrete circuits can be altered in principle, integrated"
"is normally associated with volatile types of memory (such as DRAM memory modules), where its stored information is lost if the power is removed. Many other types of non-volatile memory are RAM as well, including most types of ROM and a type of flash memory called NOR-Flash. The first RAM modules to come into the market were created in 1951 and were sold until the late 1960s and early 1970s. Reading (computer) Reading is an action performed by computers, to acquire data from a source and place it into their volatile memory for processing. Computers may read information from a"
"stored in it and delay line memory was volatile in that it had to be continuously refreshed, and thus was lost once power was removed. The earliest form of non-volatile computer storage was the magnetic drum, invented in 1932 and used in the Ferranti Mark 1, the world's first commercially available general-purpose electronic computer. IBM introduced the first hard disk drive in 1956, as a component of their 305 RAMAC computer system. Most digital data today is still stored magnetically on hard disks, or optically on media such as CD-ROMs. Until 2002 most information was stored on analog devices, but"
"""selected"" by a ""sense wire"". The core memory contents are retained even when the memory system is powered down (non-volatile memory). However, when the core is read, it is reset to a ""zero"" value. Circuits in the computer memory system then restore the information in an immediate re-write cycle. The most common form of core memory, ""X/Y line coincident-current"", used for the main memory of a computer, consists of a large number of small toroidal ferrimagnetic ceramic ferrites (""cores"") held together in a grid structure (organized as a ""stack"" of layers called ""planes""), with wires woven through the holes in"
"ECC memory Error-correcting code memory (ECC memory) is a type of computer data storage that can detect and correct the most common kinds of internal data corruption. ECC memory is used in most computers where data corruption cannot be tolerated under any circumstances, such as for scientific or financial computing. Typically, ECC memory maintains a memory system immune to single-bit errors: the data that is read from each word is always the same as the data that had been written to it, even if one or more bits actually stored have been flipped to the wrong state. Most non-ECC memory"
"technology and economies of scale have made possible so-called Very Large Memory (VLM) computers. The term ""memory"" when used with reference to computers generally refers to random-access memory (RAM). Volatile memory is computer memory that requires power to maintain the stored information. Most modern semiconductor volatile memory is either static RAM (SRAM) or dynamic RAM (DRAM). SRAM retains its contents as long as the power is connected and is easy for interfacing, but uses six transistors per bit. Dynamic RAM is more complicated for interfacing and control, needing regular refresh cycles to prevent losing its contents, but uses only one"
"non-volatile memory that retains data when power is lost. For applications requiring fast access but not necessarily data persistence after power loss, SSDs may be constructed from random-access memory (RAM). Such devices may employ batteries as integrated power sources to retain data for a certain amount of time after external power is lost. However, all SSDs still store data in electrical charges, which slowly leak over time if left without power. This causes worn out drives (that have exceeded their endurance rating) to start losing data typically after one (if stored at 30 °C) to two (at 25 °C) years"
"useless if the data is bad or requires an update. That such memory can never be changed is a disadvantage in many applications, as bugs and security issues cannot be fixed, and new features cannot be added. More recently, ""ROM"" has come to include memory that is read-only in normal operation, but can still be reprogrammed in some way. Erasable programmable read-only memory (EPROM) and electrically erasable programmable read-only memory (EEPROM) can be erased and re-programmed, but usually this can only be done at relatively slow speeds, may require special equipment to achieve, and is typically only possible a certain"